DESCRIPTION: The objective of this proposal is to develop a novel cell-free system that would facilitate rapid selection of functional fragments of monoclonal antibodies. The system descibed is based on well-established molecular mechanisms. For antibody selection, a cDNA library encoding the single-chain variable region fragment (scFv) can be used in an in vitro system to generate a large pool of scFv's that can be selected with target antigens. The cDNA for the desired scFv can be recovered and used to express large quantities of recombinant scFv. This procedure is more efficient, less expensive and technically easier than all existing methods for antibody selection. It also has the potential to be adapted to high throughput screening systems, or modified to screen binding proteins other than antibodies. PROPOSED COMMERCIAL APPLICATION: The goal for the phase I studies is to test the feasibility of this innovative technology. Once developed, it may have a major impact on proteomics, cancer diagnosis and drug development.